Early man created shelter using materials at hand: mud, stones, snow, ice, skins, sticks, foliage, bones, etc. Nomadic people either carry their shelter with them or build new shelter every time they move. For those nomads who choose to carry their shelter with them, it is a goal to make their weather-resilient shelters as light and compact as possible while still allowing for great internal volume.
There are two major portable shelter traditions. The earliest tradition uses structural material, such as wood, to create a relatively rigid framework. A canopy, perhaps of animal skins or felt or foliage, is then draped over or hung from this framework to seal out the weather. Teepees and yurts fit into this category. The invention of woven fabric revolutionized nomadic shelters, allowing for the canopy to be much lighter and more portable. Woven fabric also led to the rise of a new portable shelter tradition when the nomadic people of North Africa invented Black Tents. Black tents are tensioned fabric structures in which central poles were held in place under a ceiling of pre-stressed fabric, relying on the canopy itself for structural support. Another example of the early use of tensioned fabric to create a structure is seen in medieval military campaign tents, which used a single central mast from which a conically shaped canopy was stretched and anchored to ground, often with multiple guy lines added to increase internal volume and stability. Circus tents are another example of this type of central mast supported tent.
The invention of metal did little to further the refinement of these two shelter types—the self-supporting rigid framework tents and the tensioned fabric structures—until modern times when the development of light-weight tubular metal and the invention of composites such as fiberglass and carbon fiber led to further improvements in framing materials. Strong, collapsible framing materials led to the invention of dome tents, which follow the self-supporting framework tradition and tunnel tents, which follow the tensioned fabric tradition.
In recent times, the development of strong fabric composites has ushered in the age of large, non-portable tensioned fabric architectural structures, along with associated methods and techniques that are used to maintain these structures in equilibrium. To date there has been little use of the principles applied in this school of architecture in light-weight shelter design.
Another relatively recent development has been the invention of tensegrity structures, in which free-floating compression elements are suspended in a web of tension elements. In current practice, these structures are more artistic than practical.
Many different types of tent and canopy structures have been developed and are in use, ranging from highly portable, lightweight backpacking shelters to more commodious, heavier tent structures of various sizes, to larger structures having permanent or semi-permanent rigid supports. Various types of tent and canopy structures are disclosed, for example, in U.S. Pat. Nos. 214,996, 1,409,316, 1,581,311, 1,601,889, 2,000,644, 2,084,778, 2,167,219, 3,063,521, 3,169,611, 3,406,698, 3,990,463, 3,945,106, 4,473,976, 4,569,362, 5,036,874, 5,163,461, 5,642,590, 5,642,750, 5,901,727, 6,145,527, 6,220,264, 6,415,806, 6,470,901, 6,615,552, 6,843,261, 6,866,055, 6,868,640, 6,892,742, 6,901,714, 7,004,183, 7,013,608, 7,137,399, 7,575,010, 7,578,306, 7,578,307, 7,766,023, 7,987,864, 7,997,292, 8,001,987, U.S. Patent Publication 2009/0145471 A1 and U.S. Patent Publication 2012/0017955 A1.
Many tent structures, such as dome and tunnel styles of tent structures, are shaped using multiple poles (serving as compression elements) that extend along paths between two support locations on the ground or between support locations positioned at or near other poles. In dome style tents, the paths of these types of support poles often cross or intersect one another and, in combination, they may form a freestanding framework structure. In tunnel style tents, these types of support poles generally run parallel to one another and are maintained in place by their association with or connection to fabric portions of the tent. Neither dome nor tunnel style tents typically employ support poles forming closed or continuous compression elements.
U.S. Pat. No. 6,877,521 discloses a tent wherein a sidewall portion is joined to a generally conical roof section at a defined transition. A relatively narrow fabric tension shelf is provided internally of the transition for retaining a semi-flexible compression hoop. An internal center pole is provided and the pole, tension shelf, compression hoop and fabric act together as an engineered unit to provide a stable structure without the need for an extensive external or internal pole system and without the need for a multiplicity of individual ties for the hoop.
Notwithstanding the considerable efforts directed to developing shelter structures, the existing structures remain far from ideal. Applicant's disclosure is directed to providing shelter structures that may be assembled and disassembled easily and transported conveniently, that provide substantial internal volume, and that may be used in a variety of applications. The shelter structures disclosed herein improve upon existing collapsible tent structures, as well as exhibition structures, aviaries, greenhouses, shade structures, gazebos, pavilions, humanitarian relief structures, transient housing structures and the like.